But sure, let us explore this thought process even further
12-13 I'm not buying at all. Now, if we are going to insert some sort of reality into a fantasy and fictional universe. 12-13 year olds are usually not that sexually developed. Curious, sure. But that's about it.
I can, for the sake of argument. Agree on 15-17, but even that feel like a stretch when you think about the kink's and fetishes the girls in DK games are into. But that was not the discussion or the point.
The point is that they could
ALSO easily (and more realistically) be over 18. Especially when you think about that, some of the DK girls are willingly and happily working as prostitutes (different game, same universe).
Now if you want them to be 12 that's up to you. This is a fantasy after all, I'm not going to kink shame.
But inserting some sort of fact into a fantasy that easily can be disputed, just does not work. The only one who holds the key to that information is the creator herself.